Fróðskaparrit - 01.01.1991, Blaðsíða 67

A NOTE ON THE OCCURENCE OF LAND PLANARIANS
71
HVITAHLID
Fig. 2. The stream section at Htitahlid, Vestfirdir, Iceland. The upper section relates to a later beach ridge, the
lower section dates to before 8830 BP and comprises undisturbed marine silts, containing quantities of Plantago
lanceolata, capped by sands and peat.
present is, however, unresolved since several
possibilities exist. P. lanceolata is found here
in association with Pinus, Myrica, Tilia, Im-
patiens and Pteridium\ not a particularly
»Icelandic« pollen assemblage; Evidence
from Greenland (Fredskild, 1985) would sug-
gest that this reflects long distance transport
from North America, although a European
component may also be present. It may
represent reworking from older, perhaps in-
terglacial, deposits but this is unlikely.
Another possibility is that it was present ear-
ly in the Holocene in open ground situa-
tions, all but died out subsequently, and then
was reintroduced in greater numbers at
Landnam. Support for the early occurrence
of P. lanceolata elsewhere in Iceland comes
from pollen evidence from Lake Svinavatn
where several of the anthropogenic indicator
species including P. lanceolata, Artemesia,
Chenopodiaceae and Polygonum aviculare
occur below the Landnam tephra layer and
hence are probably earlier that the Norse set-
tlement (Hallsdottir, 1987). Interestingly,
Hallsdottir (1987) records no real increase in
the occurrence of post-Landnam P. lanceola-
ta from any of her cores in spite of relatively
abundant Cerealia pollen. Finally, it must be
remembered that Iceland is on the periphery
of the plants’ present range: P. lanceolata to-
day is confined to South Iceland around
Eyjafjoll and in the north only in a few loca-
tions in soils close to geothermal heat
(Kristinsson, 1987). It is therefore likely that
in such locations the occurrence of the plant
and its pollen production would be less than
that expected elsewhere and so its transmis-
sion into the sedimentary record correspond-
ingly reduced. Quantities of P. lanceolata
pollen in such environments are always likely
to be limited, whether or not introduced by
humans.
Pre-Settlement P. Lanceolata
in Britain and the Faroes
Pollen records in Britain demonstrate that
Plantago lanceolata greatly increased in oc-
currence from the beginning of pollen zone
Vllb onwards probably in association with
increasing deforestation, pasture and culti-